Daniel Fischer wrote:
getNumber :: String -> AssignedNumbers -> (Int,AssignedNumbers)
Yeah, that screams State Monad.
Hi, thanks for all the advice. I was hoping my AssignedNumbers "class" would be useful with many data structures. In other words I would have data State1 = State1 { a :: AssignedNumbers, b :: AssignedNumbers, ... } data State2 = State2 { c :: AssignedNumbers, d :: AssignedNumbers, ... } func1 :: State State1 Int func1 = do ... something using a and b ... func2 :: State State2 Int func2 = do ... something using c and d ... So I thought maybe I could defined a function like nextNumber :: MonadState s m => (s -> AssignedNumbers) -> (AssignedNumbers -> s) -> m Int nextNumber retreive putBack = ... and have it be useful in both "State State1 a" and "State State2 a" monads, but defining the retrieve and putBack functions isn't pretty. I will try to grok Robert's reply also. Maybe he has something addressing this. Mike